BIOCHEMISTRY OF THE SEXUAL ORGANS 283 



Its reaction is alkaline. Its specific gravity lies between 1"02 

 and r04. The amount discharged in an ejaculation is given 

 differently by different authors, and probably varies with 

 different individuals, and even with the same individual at 

 difierent times. From the figures given in the hterature 

 5 grammes may be taken to be the average amount.'^ 



According to SlowtzofE,^ human semen consists roughly of 

 90 per cent, water and 10 per cent. soUds, which, on incineration, 

 yield about 1 per cent, of ash. The solids contain 2"3 per cent, 

 of proteins, of which a nucleoprotein, traces of albumen and 

 mucin, and an albumose-Hke substance have been identified. 



The quantitative relation of the various sohds in 100 parts 

 of fresh semen can be seen in the following table ; — ■ 



Average Values. 

 Per Cent. 



Water 90-32 



Dry residue . 9'68 



Inorganic salts 090 



Organic material ... . . 8'78 



Ether soluble matter 0-17 



Extractives soluble in alcohol and water . . 6'11 

 Protein substances ...... 2'09 



In the ash K, Na, Ca, Mg, P, Fe, and S have been found. 



The quantitative analysis of the ash reveals a remarkably 

 large amount of calcium and phosphoric acid — about 20 per cent. 

 Ca and 30 per cent. P2O.. The amount of calcium excreted in 

 one ejaculation is, therefore, about O'Ol grm., and exceeds that 

 contained in an equal quantity of hme-water. Analyses of the 

 semen of other Mammals do not appear to have been made, but 

 it is unhkely that there are any essential differences. Since during 

 the breeding season about fifty sheep are served by one ram, it 

 is evident that a profound change must take place in the meta- 

 bohsm of phosphorus and calcium during that period. Is it 



' Acton, Functions and Disorders of the Reproductive Organs, 3rd 

 Edition, London, 1862. Lode, " Dntersuchungen iiber die Zahlen und 

 Regenerations Verhaltnisse der Spermatozoiden bei Hund und Mensch,'' 

 Pfiilger's Archiv, vol. 1., 1891. Mantegazza, Oaz. Med. Ital., Lombardia, 

 1866, quoted from Lode. 



* Slowtzoff, " Zur Chemie des mensohlichen Sperma," Zeitschrift f. phys. 

 Chemie, vol. xxxv., 1902. 



